Lubricating oil composition



United States aten t 2,851,416 Patented Sept. 9, 1958 2,851,416 LUBRICATING DEL COMPOSITION Albert R. Sabol, Munster, andpRobert E. Karll, Hammond, Ind., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana N Drawing. Application January 30, 1956 Serial No. 562,013

'15 Claims. (Ci. 252 32.7

This invention relates *to a novel lubricating oil composition and more particularly pertains to a lubricating internalcombustion engines, particularly of the type opcrating under severe conditions, since under such conditions the lubricants are susceptible to deterioration resulting in the development of carbonaceous and/or resinous or similar varnish-like deposits in the engines and on and about the valves and rings of the engine and under some conditions such oils are not effective in inhibiting corrosion of the various components of the engine.

' It has heretofore been found that certain hydrolyzed reaction products of a phosphorus sulfide and a hydrocarbon, particularly an olefinic hydrocarbon or an olefin polymer, when added in small amounts to a hydrocarbon oil, are effective in inhibiting the formation of varnish, sludge, carbon and the like in lubricating oils during use.

It has also been found that neutralizing these hydrolyzed reaction products of a phosphorus sulfide and a hydrocarbon with a basic reagent having a metal constituent, and particularly basic barium compounds, provides a composition which is effective as a detergent. However, in 3 the manufacture of these lubricants containing the neutralized, metal-containing hydrolyzed reaction product ofa phosphorus sulfide and a hydrocarbon, a substantial amount of the sulfur introduced therein by the phosphorus sulfide is lost in the hydrolysis. Consequently, under certain conditions these compositions do not effectively inhibit corrosion of the metal surfaces which they lubricate. Moreover, when preparing such compositions in accordance with the prior art, it has generally been found necessary to treat the product which has been subjected to hydrolysis to remove undesirable hydrolysis products. This is accomplished, for example, by clay treatment.

It is an object of our invention to provide a lubricant for internal combustion engines which will serve both the functions of inhibiting corrosion and providing adequate detergency. 'It is a further object of our invention to; provide a method 'of preparing a lubricant additive whereby hydrolysis is prevented and the additional process stepsto remove undesirable products formed during such hydrolysis are avoided. These and additional objects will become apparent as the description of the invention proceeds.

1 We have discovered that a product having the desired detergency' characteristics and corrosion inhibiting properties can be obtained by incorporating in a lubricant composition a minor proportion, from about 0.001 percent to about 10 percent by weight, and preferably from about 0.1 percent to about 5 percent by Weight of the product obtained by reacting an olefinic hydrocarbon having a molecular Weight of from about l5to about 50,000. particularly an olefinic polymer of butylene, with from about 1 percent to about 50 percent by weight, and preferably from about 5 percent'to about percent by weight of a phosphorus sulfide at a temperature of from about 200 F. to about 600 F., and preferably from about 300 F. to about500 F.; and further reacting the thus formed phosphorus sulfide-olefinic hydrocarbon reaction product with at least about 3 parts by weight of a basic barium compound per part of phosphorus present in the phosphorus sulfide-olefinic hydrocarbon reaction product which reaction is carried out in the presence of from about 0.5 to about 5 parts by weight, per part of basic barium compound, of an aliphatic alcohol, preferably having from about 1 to about 12 carbon atoms, at a temperature of from about F. to a temperature not substantially greater than the boiling point of the mixture, and preferably at a temperature in the range of about to about 240 F., for at least about one-half hour, and preferably not more than about 10' hours, and then increasing the temperature to remove the alcohol from the reaction mixture. It is essential, in order to avoid undesirable hydrolysis of the product during its preparation, that Water is not admitted to the system. Thus, the preferred basic barium compound is barium oxide, although barium hydroxide can be employed. The use of the various hydrates of basic barium compounds is to be avoided. For the same reason it is likewise essential that the alcohols employed in the reaction are not contaminated with water, i. e., only anhydrous alcohols may be employed.

As stated hereinbefore, the preferred alcohols which can be employed are those having up to about 12 carbon atoms. By reason of cost and availability, the lower molecular weight alcohols such as methyl, ethyl and isopropyl are particularly preferred, although butanol, hexanol, heptanol, octanol and their various isomers are well suited for this reaction.

In the preparation of the phosphorus sulfide-olefinic hydrocarbon reaction product, the olefin is reacted with a phosphorus sulfide such as P 8 P 8 P 8 or other phosphorus sulfides, and preferably phosphorus pentasulfide, P 8

The olefinic hydrocarbon constituent in this reaction is preferably a mono-olefin hydrocarbon polymer resulting from the polymermization of low molecular weight monoolefinic hydrocarbons or iso-mono-olefinic hydrocarbons, such as propylenes, butylenes and amylenes or the copolymers obtained by the polymerization of hydrocarbon mixtures containing iso-mono-olefins and mono-olefins of less than 6 carbon atoms. The polymers can be obtained by the polymerization of these olefins or mixtures of olefins in the presence of a catalyst such as sulfuric acid, phosphoric acid, boron fluoride, aluminum chloride or other similar halide catalysts of the Friedel-Crafts type.

Other preferred olefins suitable for the preparation of the hereindescribed phosphorus sulfide reaction products are olefins having at least 20 carbon atoms in the molecule of which from about 13 to about 18 carbon atoms, and preferably at least 15 carbon atoms are in a long chain. Such olefins can be obtained by the dehydrogenation of paratfins, such as by the cracking of parafiin Wax or by the dehalogenation of alkyl halides, preferably long chain alkyl halides, particularly halogenated parafiin waxes. I

In general, the preparation of the barium-containing phosphorus sulfide-olefinic hydrocarbon reaction product, in accordance with the present invention, is carried out in the following manner. The olefinic hydrocarbon such as, for example, an olefinic polymer of the desired molecular weight, is reacted with from about 1 percent to about 50 percent, and preferably from about 5 percent to about 25 percent, of a phosphorus sulfide such as P 8 at a temperature of from about 200 F. to about 600 F. in a non-oxidizing atmosphere such as, for example, an atmosphere of nitrogen. The reaction is carried out for from about one to about ten hours or more,and preferably for about hours. The phosphorus sulfide-olefinic hydrocarbon reaction can, if desired, be carried out in the presence of a sulfurizing agent such as elemental sulfur or a halideof sulfur. The reaction product thus obtained is then preferably diluted with a normally liquid hydrocarbon, generally the same as, or similar to, the hydrocarbon .oil in which the finished additive is to be employed, to a total phosphorus content of from about 0.5 percent to about 5 percent, and preferably to a phosphorus content of from about 1 percent to about 2 percent.

The phosphorus sulfide-olefinic hydrocarbon reaction product, preferably oil diluted, is then heated to at least about 100 F. and preferably about 150 F. and the requisite amount of a basic barium compound, preferably barium oxide, and an alcohol, preferably having from about 1 to about 12 carbon atoms, are added to the mixture. These constituents may be pro-mixed before addition to the main reaction mixture or they may be added independently. The amount of basic barium compound employed is at least about 3 parts by weight per part of phosphorus present in the reaction mixture. At this ratio of barium to phosphorus, barium utilization approaches 100 percent. Basic barium compound in excess of this amount can be employed without deleterious effects but barium utilization will decrease substantially and necessitate filtering the product after the reaction is completed. Less than three parts by weight of basic barium compound can also be employed and the efficiency of barium utilization will be about 100 percent; however, it is desirable to introduce the maximum,

amount of barium into the product to obtain maximum detergency and thus it is not desirable to employ less barium than is capable of reacting with the phosphorus sulfide-olefinic hydrocarbon reaction product unless, of course, the detergency characteristics of the finished oil are of only minor importance and the prime use of the composition is as a corrosion inhibitor. The amount of alcohol employed in the reaction is dependent upon the amount of basic barium compound used. We have found that from about 0.5 to about 5 parts by weight of alcohol per part of basic barium compound is effective although it is, preferable to use about an equal amount by weight of alcohol and basic barium compound.

After addition of the basic barium compound and the alcohol to the reaction mixture, the temperature is maintained between about 100 F. and below the boiling point of the mixture. Higher temperatures, of course, increase the reaction rate and are thus desirable. It is preferable, therefore, to maintain the temperature of the reaction close to the temperature at which the alcohol vaporizes. The reaction mixture is thus heated for at least about one-half hour and preferably for about two to about six hours. The temperature is then increased to remove the alcohol from the reaction mixture. An inert gas such as nitrogen may be bubbled through the product in order to speed up removal of the alcohol. The reaction product can be filtered after removal of the alcohol in order to remove unreacted components; however, this is not always necessary if the preferred amounts as hereinbefore specified are employed.

The following examples are illustrative of our invention:

EXAMPLE 1 Butylene polymer (of about 700 molecular weight) was reacted with about percent P 5 at a temperature of 400 in an atmosphere of nitrogen for about 5 hours. This reaction product was then diluted with an SAE 5 base oil to a phosphorus content of 1.5 percent. The reaction mixture was heated to a temperature of 170- 180 F. and 4.66 parts by weight of barium oxide (based on phosphorus content) and 1 part by weight of methanol (based on barium oxide) was added to the mixture. The reaction mixture was maintained at a temperature of.170180 F. for about 4 hours. The alcohol was 4 7 then distilled off by gradually increasing the temperature to 300 F. During distillation of the alcohol nitrogen was bubbled through the product. The product was then filtered and a portion thereof analyzed. It contained 5.31 percent barium, 1.48 percent phosphorus and 2.89 percent sulfur. Barium. oxide utilization was about percent.

EXAMPLE 2 Same as Example 1 with the exception that ethanol was substituted for methanol. The product contained 4.63 percent barium, 1.24 percent phosphorus and 1.44 percent sulfur.

EXAMPLE 3 The diluted P S -butylene polymer prepared as described in Example l was reacted with 9.33 parts by weight of barium oxide (based on phosphorous content of reaction mixture) in the presence of 1.43 parts by weight of 2-ethylhexano1 (based on barium oxide employed) at about 220 F. for 5 hours. The temperature was then increased to remove the alcohol and the product was filtered. The reaction product contained 6.68 percent barium, 1.48 percent phosphorus and 2.34 percent sulfur. This example illustrates that using large excesses of barium, although yielding a satisfactory product, does not substantially increase the barium content. In this example barium oxide utilization was less than 50 percent.

EXAMPLE 5 An additive mixture in accordance with the prior art was prepared as follows. The P S -butylene polymer of Example 1 was hydrolyzed in the presence of steam at a temperature of about 350 F. This product was then diluted with an SAE 20 base oil to a phosphorus content of 1.5 percent and then contacted with fullers earth at a temperature of about 300 F. and filtered. The hydrolyzed, clay-contacted product was thenneutralized with an excess of barium hydroxide octahydrate at a temperature of about 350 F. and then filtered. The product thus obtained had a barium content of 3.04 percent,

a phosphorous content of 1.45 percent and less than 0.5

percent sulfur. 7

EXAMPLE 6 This example was run in the same manner as Example 1 with the exception that the alcohol was omitted from the reaction mixture. Very little reaction took place and the, product was not analyzed. Barium utilizationwas less than 10 percent.

As pointed outhereinbefore, the compositions provided by our invention effectively inhibit the corrosion of metal surfaces in internal combustion engines. This is demonstrated by the results obtained with the so-called conventional L-4 Test. This test is made on a Standard Chevrolet, 6-cylinder engine, equipped with three pairs of copper-lead bearings, operating'for 36 hours at 3150 R. P. M. at a load of 30B. H. P., with an oil sump temperature of, 280 F., and a water outlet temperature of 200. The copper-lead alloy bearings are weighed before and after the test period and loss in weight noted; a bearing weight in excess of 0.2 gram is failing. The following compositions were subjected to theL-4 Test, results of which are shown in Table 1.

Sample A 6.6 percent of the product of Example 1 93.4 percent SAE 30 base oil' Sample B Y 6.6 percent of the product of Example 5' 93.4 percent; SAE 30 base .oil

a visual rating of from 1 Bearing Weight Loss in Grams sam le A 0. 055 0. 055 0. 139 B 1. 1. 00 1. O1

It is thus evident that the corrosion inhibiting properties of our composition are excellent while the corrosion inhibiting properties of the commercially available product which has been hydrolyzed are failing.

To demonstrate the effectiveness of our composition as a detergent, a performance test was made with the so-called conventional L-l Test. This test is made on a Caterpillar. 1-ASl single cylinder Cater-pillar engine equipped with new pistons, rings and liners, operating for 480 hours at 1000 R. P. M. at a load of 19.8 B. H. P., with an oil sump temperature of 145-l50 F., and a water outlet temperature of 175-180 F. The fuel employed in this test was at the so-called S-1 level, containing 1 percent sulfur. This test is designed to measure oil detergency and inspections are made at 120, 240 and 480 hours. Piston lands, grooves and liner are inspected for carbon and lacquer. Varnish values are based on to in which a rating of 10 indicates no varnish and a rating of 1 indicates excessive amounts of varnish. The compositions above, designated Sample A and Sample B, were subjected to the L-l Test, results of which are shown in Table 2.

Table 2 L-l ENGINE TEST-HIGH SULFUR FUEL The results shown in Table 2 for Example A demonstrate the eifectiveness of our composition as a detergent. Example B is typical of the commercially available motor oil detergents and it is apparent that our composition is equal to or better than Example B. While the commercially available detergents, exemplified by Example B in Tables 1 and 2, are very effective as regards detergency characteristics, it is necessary to incorporate with them an additional corrosion inhibitor. This is not necessary when using our composition inasmuch as it exhibits excellent corrosion inhibition properties as shown by the foregoing L-4 engine test.

While the present invention has been described by the use of our composition in petroleum lubricating oils, other lubricating oil bases may be employed such as hydrocarbon oils, natural or synthetic, such as those obtained by the polymerization of olefins, as well as synthetic lubricating oils of the alkylene oxide types, and the polycarboxylic acid ester type oils such as the oilsoluble esters of adipic acid, sebacic acid, azelaic acid, etc. It is also contemplated that various other of the well known additives, such as anti-oxidants, anti-foaming agents, pour point depressors, extreme pressure agents, anti-wear agents, V. I. improvers, etc. may be incorporated in lubricating oils containing the additive of our invention.

Unless otherwise stated, the percentages stated herein and in the claims are weight percentages.

While we'have described our invention by reference to specific embodiments thereof, the same are given by way of illustration. Modifications and variations will 6 be apparent from our description to those skilled in the art.

We claim:

1. A lubricant composition comprising a major proportion of a lubricating oil and in combination therewith a minor proportion, from about 0.001 percent to about 10 percent by weight, of the product obtained by reacting under anhydrous conditions an olefinic hydrocarbon having a molecular weight of from about 150 to about 50,000 with from about 1 percent to about 50 percent by weight of a phosphorus sulfide at a tempera: ture of from about 200 F. to about 600 F., reacting the phosphorus sulfide-olefinic hydrocarbon reaction product with at least about 3 parts by weight of a basic barium compound per part of phosphorus present in said phosphorus sulfide-olefinic hydrocarbon reaction product in the presence of from about 0.5 to about 5 parts by weight of an aliphatic alcohol per part of basic barium compound, which aliphatic alcohol has from about 1 to about 12 carbon atoms, at a temperature of from about F. to a temperature not substantially greater than the boiling point of the mixture for at least about onehalf hour and increasing the temperature to remove said alcohol from the reaction mixture.

2. The composition of claim 1 wherein said olefinic hydrocarbon is a polymer of butylene.

3. The composition of claim 1 wherein the phosphorus sulfide is phosphorus pentasulfide.

4. The composition of claim 1 wherein said basic barium compound is barium oxide.

5. The composition of claim 1 wherein said aliphatic alcohol is methanol.

6. The composition alcohol is ethanol.

-7. The composition alcohol is isopropanol.

8. The composition of claim 1 of claim 1 wherein said aliphatic of claim 1 wherein said aliphatic wherein said aliphatic alcohol is 2-ethylhexanol.

9. A lubricant composition comprising a major proportion of a lubricating oil and in combination therewith a minor proportion, from about 0.001 percent to about 10 percent by weight, of the product obtained by reacting under anhydrous conditions a butylene polymer having a molecular weight of from about to about 50,000 with from about 1 percent to about 50 percent by weight of phosphorus pentasulfide at a temperature of from about 200 F. to about 600 F., diluting the P S -butylene polymer reaction product with a normally liquid hydrocarbon to a phosphorus content of from about 0.5 percent to about 5 percent, reacting the diluted reaction product with at least about 3 parts by weight of barium oxide per part of phosphorus present in said diluted reaction product in the presence of from about 0.5 to about 5 parts by weight of an aliphatic alcohol per part of barium oxide, which aliphatic alcohol has from about 1 to about 12 carbon atoms, at a temperature of from about 100 F. to a temperature not substantially greater than the boiling point of the mixture for a period of time of from about onehalf hour to about 10 hours, increasing the temperature to remove the alcohol and filtering the reaction mixture.

10. The method of preparing a lubricating oil additive which is useful as a detergent and will effectively inhibit corrosion of metal surfaces which method comprises reacting under anhydrous conditions an olefinic hydrocarbon having a molecular weight of from about 150 to about 50,000 with from about 1 percent to about 50 percent by weight of a phosphorus sulfide at a temperature of from about 200 F. to about 600 F., reacting the phosphorus sulfide-olefinic hydrocarbon reaction product with at least about 3 parts by weight of a basic barium compound per part of phosphorus present in said phosphorus sulfideolefinic hydrocarbon reaction product in the presence of from about 0.5 to about 5 parts by weight of an aliphatic alcohol per part of basic barium compound, which aliphatic alcohol has from about 1 to about 12 carbon atoms, at a temperature of from about 100 F. to a temperature not substantially greater than the boiling point of the mixture for at least about one-half hour and increasing the temperature to remove said alcohol from the reaction mixture.

11. The method of preparing a lubricating oil additive which-is useful as a'detergent and'will effectively inhibit corrosion of metal surfaces which method comprises reacting under anhydrous conditions a butylene polymer having a molecular weight of from about 150 to about 50,000 with from about 1 percent to about 50 percent by weight of phosphorus pentasulfide at a temperature of from about 200 F. to about 600 F., diluting the P 5 butylene polymer reaction product with a normally liquid hydrocarbon to a phosphorus content of from about 0.5

percent to about 5 percent, reacting the diluted reaction 15 product with at least about 3 parts by weight of barium oxide per part of phosphorus present in said diluted reaction product in the presence of from about 0.5 to about 5 parts by weight of an aliphatic alcohol per part of barium oxide, which aliphatic alcohol has from about 1 to about 20 2,528,257

12 carbon atoms, at a temperature of from about 100 F.

11 wherein said aliphatic 14. The method of claims 11wherein'saidf'aliphatio alcohol is isopropanol.

15. The. methodof claim 11 wherein said aliphatic alcohol is 2-ethylhexanol.

References Cited in the file of this patent UNITED STATES PATENTS" 2,461,961 Buckmann Feb. 15, 1949 2,463,429 Roberts Mar. 1, 1949.

Vold Oct. 31, 1950 2,535,024 Funk Dec. 26, 1950 UNITED STATES PATENT OFFICE CERTIHQATE 0F CORRECTION Patent No. 2,851,416 September 9, 1958 Albert R, Sabol et al.,

It is hereby certified that error appears in the-printed specification of the above "numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 68, for "15" read 150 same line, for "50,000." read 50,000,

Signed and sealed this 2nd day of June 1959.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents UNITED STATES PATENT OFFICE QERTIFICATE 0F CORRECTION Patent No, 2,851,416 September 9, 1958 Albert R, Sabol et alo It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 68, for "15" read 150 same line, for "50,000," read 50,000, e

Signed and sealed this 2nd day of'June 1959 SEAL) Attest:

KARL H, AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PROPORTION OF LUBRICATING OIL IN COMBINATION THEREWITH A MAJOR PROPORTION, FROM ABOUT 0.001 PERCENT TO ABOUT 10 PERCENT BY WEIGHT, OF THE PRODUCT OBTAINED BY REACTING UNDER ANHYDROUS CONDITIONS AN OLIFINIC HYDROCARBON HAVING A MOLECULAR WEIGHT OF FROM ABOUT 150 TO ABOUT 50,000 WITH FROM ABOUT 1 PERCENT TO ABOUT 50 PERCENT BY WEIGHT OF PHOSPHROUS SULFIDE AT A TEMPERATURE OF FROM ABOUT 200*F. TO ABOUT 600*F., REACTING THE PHOSPHOROUS SULFIDE-OLIFINIC HYDROCARBON REACTION PRODUCT WITH AT LEAST ABOUT 3 PARTS BY WEIGHT OF A BASIC BARIUM COMPOUND PER PART OF PHOSPHOROUS PRESENT IN SAID PHOSPHORUS SULFIDE-OLEFINIC HYDROCARBON REACTION PRODUCT IN THE PRESENCE OF FROM ABOUT 0.5 TO ABOUT 5 PARTS BY WEIGHT OF AN ALIPHATIC ALCOHOL PER PART OF BASIC BARIUM COMPOUND, WHICH ALIPHATIC ALCOHOL HAS FROM ABOUT 1 TO ABOUT 12 CARBON ATOMS, AT A TEMPERATURE OF FROM ABOUT 100*F. TO A TEMPERATURE NOT SUBSTANTIALLY GREATER THAN THE BOILING POINT OF THE MIXTURE FOR AT LEAST ABOUT ONEHALF HOUR AND INCREASING THE TEMPERATURE TO REMOVE SAID ALCOHOL FROM THE REACTION MIXTURE. 